This trial is a Phase 2, randomized, controlled study to compare the degree of mucosal injury after the oral administration of an investigational product, PL2200, and a marketed 325 mg immediate-release aspirin product.

Each group will be treated with either an immediate-release aspirin tablet or PL2200 capsule at 325 mg per day for 6 weeks, and evaluated via an endoscope for any gastrointestinal injury that may have been caused by study medication.

Inclusion Criteria:

• Healthy volunteers, ≥50 and ≤75 years of age.
• No endoscopically observed baseline gastrointestinal lesions.

Exclusion Criteria:

• Baseline gastrointestinal lesions or abnormal screening/baseline laboratory parameters deemed clinically significant by the Investigator.
• Significant history of substance abuse or uncontrolled acute or chronic medical illness.
• Active H. pylori infection.
• Current use of low-dose aspirin for cardioprevention, or other ulcerogenic medications, gastroprotective, or anti-platelet agents.
• Hypersensitivity to aspirin or other NSAIDs.